First, you wan to talk to your prescribing doctor. Not every RLS drug has the side effect of weight gain. You could also talk to a health food store who specialize in homeopathic remedies..there might be something you could take which might help.

Try taking one or two capsules of 25mg ferrous bisglycinate on an empty stomach about an hour before bed. Iron works for a lot of people. I am one of the lucky ones where the iron (gotta be that form) works within one hour to get rid of the RLS for the night. If you plan to use long term you have to talk to your doctor about it. My ferritin levels are in the normal range and as long as yours are in the normal range and not above you should be ok to do a trial run.